Virtual magnetic core constructed by utilizing vector magnetic circuit principle and application method of virtual magnetic core

Abstract

The invention relates to a virtual magnetic core constructed by utilizing a vector magnetic circuit principle and an application method thereof, provides the virtual magnetic core and the application method thereof by utilizing the vector magnetic circuit principle, belongs to the field of magnetic circuit theory application, and particularly relates to magnetic circuit design of an electromagnetic device. A magnetic core (iron core) is an important component of a motor, a transformer, a reactor and other electromagnetic devices and accounts for about 50% of the total weight of the electromagnetic devices. A magnetic core (iron core) is removed from an electromagnetic device such as an air-core transformer, but the air magnetic conductivity is poor, the exciting current is large, and therefore the electromagnetic device is poor in loading capacity, large in size and limited in application range. A virtual magnetic circuit is constructed by utilizing a plurality of vector magnetic circuit elements, the magnetic conductive capability of the virtual magnetic circuit is similar to or better than that of an actual magnetic core, and a virtual magnetic core is formed. On the basis of the application method, electromagnetic devices such as transformers, reactors and motors are constructed through the virtual magnetic cores, and the weight and the size of the electromagnetic devices are expected to be remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the field of application of magnetic circuit theory, and in particular relates to the magnetic circuit design of an electromagnetic device. Background Art

[0002] As the carrier of the magnetic circuit, the magnetic core (iron core) provides a clear and predictable path for the magnetic flux, and effectively concentrates and guides the magnetic field energy. It is an indispensable and important component of electromagnetic devices such as transformers, reactors and motors, and has a wide range of applications. For ease of description, the present invention uniformly uses the term "magnetic core" for description. According to "High-frequency magnetic components" (second edition) written by Kazimierczuk MK, there are currently two main ways to construct the magnetic core.

[0003] The first is the traditional magnetic core, which is made of high magnetic permeability materials (such as metal parts, powder materials, ferrites, etc.) and can form a complete closed magnetic circuit. This type of magnetic core has a high magnetic permeability, which can effectively bind magnetic flux and reduce leakage magnetic flux, thereby significantly reducing magnetic circuit losses and improving system efficiency and stability. However, the disadvantage of traditional magnetic cores is that their weight usually accounts for 50% to 70% of the effective materials of the electromagnetic device, there is a saturation effect, resulting in nonlinear magnetic circuit characteristics, and core losses are prone to occur under the action of the alternating magnetic field, resulting in heat, so additional heat dissipation and cooling measures are required.

[0004] The second type is the air core, which forms a closed magnetic circuit through air or gas medium and is usually used in high-frequency converters and other high-frequency electromagnetic devices. The air core has a lower magnetic permeability, which is suitable for low-loss and high-frequency applications, and helps to reduce the energy loss of the magnetic circuit. However, since the air core cannot accurately control the magnetic flux path, the leakage magnetic phenomenon is serious, the energy conversion efficiency is low, and the performance is difficult to match that of traditional magnetic cores, its application scenarios are relatively limited.

[0005] It can be seen from Chinese patents CN202011350276.4 and CN202311372958.9 that according to the vector magnetic circuit theory, the performance of the magnetic core is determined by three basic magnetic circuit parameters: magnetic resistance, magnetic induction and magnetic capacitance. These parameters can be effectively adjusted by adding external magnetic circuit elements, thereby realizing the regulation of the performance of the magnetic core. At present, the research on magnetic cores is mainly focused on the design and improvement of traditional magnetic cores and air cores. Once the magnetic core is manufactured and put into a stable working state, its magnetic circuit parameters are usually fixed, and the characteristics of the magnetic core are difficult to adjust and optimize. Therefore, how to innovate the magnetic core design by adding external magnetic circuit elements (such as magnetic induction elements, etc.), forming a new type of magnetic core, and effectively improving the various performance indicators of the magnetic circuit, such as power, efficiency and coupling coefficient, has not yet been fully studied and solved. Summary of the invention

[0006] Technical problem: In response to the defects of the background technology, the present invention proposes a virtual magnetic core constructed using the vector magnetic circuit principle and its application method. It uses the vector magnetic circuit principle to construct a virtual magnetic circuit from multiple vector magnetic circuit elements, and its magnetic conductivity is similar to or better than that of the actual magnetic core to form a virtual magnetic core. By rationally configuring and adjusting the parameters of each vector magnetic circuit element, the engineering design and online adjustment of the virtual core magnetic circuit parameters can be achieved, which can effectively control the amplitude and phase of the magnetic flux in the magnetic circuit, thereby affecting the magnetic circuit power and optimizing the overall performance of the magnetic circuit. Based on this, an application method is proposed, which uses virtual magnetic cores to construct electromagnetic devices such as transformers, reactors, and motors, which is expected to significantly reduce the weight and volume of the electromagnetic devices.

[0007] Technical solution: In order to solve the above technical problems, the present invention first proposes a virtual magnetic core constructed using the vector magnetic circuit principle, and a plurality of vector magnetic circuit elements, a plurality of circuit elements, and a plurality of excitation windings are respectively coupled to the magnetic flux loop of the virtual magnetic core to jointly construct a virtual magnetic circuit to form a virtual magnetic core, and the virtual magnetic core is used to replace a part of the traditional magnetic core or completely replace the traditional magnetic core; by configuring each vector magnetic circuit element and the circuit elements connected to it, the magnetic circuit parameters of the virtual magnetic core are adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit are controlled, the excitation current of the magnetic circuit is adjusted, and the active power and reactive power of the magnetic circuit are affected.

[0008] The vector magnetic circuit element that forms the virtual magnetic core is a vector magnetic circuit element with a negative magnetic resistance and a positive magnetic induction value formed by connecting a capacitor element in a magnetic induction closed coil. According to the vector magnetic circuit theory, the expression of the equivalent magnetic circuit impedance under sinusoidal excitation is: ; Where Z is the equivalent magnetic impedance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force, C is the capacitance value of the capacitor element, R is the resistance value of the magnetic induction closed coil; its magnetic impedance includes a negative magnetic resistance term and a positive magnetic resistance term, in which the negative magnetic resistance term can partially or completely offset the air magnetic resistance of the target magnetic circuit. If the magnetic induction coil is made of superconducting material, the resistance R is approximately 0, and there is no positive magnetic reactance term.

[0009] The vector magnetic circuit element that forms the virtual magnetic core is an active circuit element with negative resistance connected to the magnetic induction closed coil. Its magnetic circuit characteristic presents negative magnetic induction, and the equivalent magnetic reactance value is: ; Where X is the equivalent magnetic reactance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, - R It is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element; its magnetic impedance is a negative magnetic reactance term, which can partially or completely offset the positive magnetic reactance, so that the magnetic impedance of the entire magnetic circuit is approximately equal to or less than the magnetic impedance of the real magnetic core.

[0010] The vector magnetic circuit elements in the virtual magnetic core are arranged in a variety of ways along the magnetic flux direction, including series connection, parallel connection, cascade connection, or forming a nested structure in space; vector magnetic circuit elements with different arrangements correspond to different magnetic circuit parameters, and the arrangement of vector magnetic circuit elements in actual applications has different effects on the magnetic circuit variables of the magnetomotive force and magnetic flux in the magnetic circuit.

[0011] The vector magnetic circuit elements in the virtual magnetic core adopt rectangular, circular, polygonal and concentric structures as well as different winding forms and turns configurations according to design requirements. Vector magnetic circuit elements with different geometric topologies and winding methods give the magnetic circuit different equivalent magnetic circuit parameters, and through the topological structure and layout of vector magnetic circuit elements in actual applications, different influences are produced on the magnetic circuit variables of magnetomotive force and magnetic flux in the magnetic circuit.

[0012] The geometry, spatial arrangement, size, type and quantity of the virtual magnetic core are determined by the actual application requirements. (This decision means that if six vector magnetic circuit elements are required on the magnetic circuit, you can choose to place three by three, two by two, or three by one. The specific effect depends on the actual needs of the user).

[0013] The present invention uses the application method of the virtual magnetic core constructed by the vector magnetic circuit principle, and uses the virtual magnetic core and a conductor coil to form various electromagnetic devices using an alternating magnetic field as a medium, including transformers, reactors, motors, etc.

[0014] The target magnetic circuit is the object to be applied, so as to realize the target magnetic circuit under the preset target magnetic flux condition, to reduce the magnetic impedance of the magnetic circuit as much as possible, and to reduce the magnetic circuit excitation current, i.e., the magnetomotive force, as follows: S1. Calculate the magnetic circuit parameters before adding the virtual magnetic core, including the magnetic flux, magnetic resistance and magnetic reactance of the magnetic circuit, according to the physical structure of the target magnetic circuit and the actual working conditions including frequency and temperature; S2. Determine the specific application form of the virtual magnetic core, including partial replacement or complete replacement, and determine the number and position of the vector magnetic circuit elements in the virtual magnetic core in combination with the calculated magnetic circuit parameters, and calculate the magnetic circuit parameters of these vector magnetic circuit elements; S3, adding the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core; S4. Under the premise of not affecting the normal operation of the equipment, the negative magnetic circuit parameters of the vector magnetic circuit elements in the virtual magnetic core, including negative magnetic resistance and negative magnetic induction, are used to weaken the positive magnetic circuit parameters in the magnetic circuit. By continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, the magnetic impedance characteristics of the magnetic circuit are optimized to ensure that the excitation current, i.e., the magnetomotive force, of the target magnetic circuit is minimized under the preset target magnetic flux conditions, so that the virtual magnetic core is close to or better than the real magnetic core in terms of key performance indicators.

[0015] The method is applicable to any magnetic core that can form a closed magnetic circuit, and does not impose specific restrictions on the physical properties of the target magnetic circuit, such as shape, material or structure.

[0016] The magnetic circuit parameters of the selected vector magnetic circuit elements are time-invariant magnetic circuit parameters or time-varying magnetic circuit parameters. As long as the application does not affect the normal operation of the target magnetic circuit, the specific form of the magnetic circuit parameters is not limited. (Time-invariant magnetic circuit parameters are magnetic circuit parameters that do not change with time, which can usually be realized by materials such as metal conductors; time-varying parameters are parameters that change with time, which can usually be realized by materials such as superconductors).

[0017] Furthermore, the application method of the virtual magnetic core proposed in the present invention is applicable to any electromagnetic device including a magnetic circuit structure, including but not limited to reactors, transformers and motors. In addition, there is no specific restriction on the specific form of the target magnetic circuit, such as physical properties such as shape, material and structure.

[0018] Beneficial effects: Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: (1) The virtual magnetic core and its application method designed by the present invention are different from traditional magnetic cores and air cores, and innovatively propose a construction scheme for the virtual magnetic core. Under the premise of ensuring that the performance of the magnetic circuit is not affected, the virtual magnetic core partially or completely replaces the traditional magnetic core or air core, adjusts the magnetic circuit parameters, controls the amplitude and phase of the magnetic flux in the magnetic circuit, adjusts the excitation current (magnetomotive force) of the magnetic circuit, optimizes the distribution of active power and reactive power, improves the power-to-weight ratio of the electromagnetic device, and improves the overall performance of the magnetic circuit; (2) The virtual magnetic core and its application method designed by the present invention, which is composed of only a plurality of vector magnetic circuit elements, significantly reduces the overall weight of the magnetic core compared to the traditional magnetic core, and overcomes the problems of easy saturation, large loss, severe heat generation and difficulty in heat dissipation existing in the traditional magnetic core. In addition, its structural characteristics make the virtual magnetic core easy to fold, pack and transport, which is convenient for efficient circulation and use in practical applications; (3) The virtual magnetic core and its application method designed by the present invention can flexibly plan the magnetic flux path of the virtual magnetic core according to actual needs, and its magnetic circuit parameters can be adjusted online, which greatly improves the flexibility and freedom of magnetic core design. Compared with the air core, under the same target magnetic flux conditions, the virtual magnetic core requires a smaller excitation current and has a higher transmission efficiency, while maintaining stable electromagnetic coupling and lower leakage flux. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the virtual magnetic core of the present invention.

[0020] Figure 2 A schematic diagram of a magnetic circuit partially or completely formed by a virtual magnetic core of the present invention; Figure 2 (a) is a closed magnetic circuit composed entirely of virtual magnetic cores. Figure 2 (b) in the figure is a closed magnetic circuit consisting of a virtual magnetic core and a traditional magnetic core.

[0021] Figure 3 A vector magnetic circuit element with negative magnetic resistance and positive magnetic reactance and its equivalent magnetic circuit of the present invention; Figure 3 (a) in the figure is a vector magnetic circuit element composed of a magnetic induction element and a capacitor element. Figure 3 (b) in the figure is the equivalent magnetic circuit diagram of the vector magnetic circuit element.

[0022] Figure 4 A vector magnetic circuit element with negative magnetic reactance and its equivalent magnetic circuit of the present invention; Figure 4 (a) in the figure is a vector magnetic circuit element composed of a magnetic induction element and an active circuit element. Figure 4 (b) in the figure is the equivalent magnetic circuit diagram of the vector magnetic circuit element.

[0023] Figure 5 This is a diagram of the winding shape of the vector magnetic circuit element in the virtual magnetic core of the present invention. Figure 5 (a) is circular winding. Figure 5 (b) is a rectangular winding. Figure 5 (c) in the figure is polygonal winding. Figure 5 (d) in the figure is concentric winding.

[0024] Figure 6 The figure is a flow chart of the virtual magnetic core application method of the present invention.

[0025] Figure 7 It is a schematic diagram of the virtual magnetic core application method of the present invention.

[0026] Figure 8 The primary voltage, secondary voltage and excitation current of the present invention when no virtual magnetic core is added.

[0027] Fig. 9 The primary voltage, secondary voltage and excitation current when the negative magnetic resistance vector magnetic circuit element is added in the present invention.

[0028] Fig.10 The primary voltage, secondary voltage and excitation current when a negative magnetic induction vector magnetic circuit element is added in the present invention.

[0029] Fig.11 The primary voltage, secondary voltage and excitation current waveforms of the virtual magnetic core when the load is 10Ω according to the present invention.

[0030] Fig.12 The primary voltage, secondary voltage and excitation current waveforms of the traditional magnetic core of the present invention when the load is 10Ω. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0032] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0033] As the carrier of the magnetic circuit, the magnetic core not only provides a clear and predictable path for the magnetic flux, but also can effectively concentrate and guide the magnetic field energy. Existing magnetic cores are mainly divided into two categories. The first category is the traditional magnetic core, which is an important component of electromagnetic devices such as motors, transformers, and reactors.

[0034] The second type is the air core, whose magnetic flux path relies on air or other gaseous media to close, so there is no magnetic saturation problem and the heat dissipation is good. However, the magnetic core is removed from electromagnetic devices such as air core transformers, and the magnetic flux path cannot be effectively planned. Whether it is a traditional magnetic core or an air core, once manufactured, its magnetic circuit parameters are fixed in a stable working environment, making it difficult to achieve online adjustment of the core performance.

[0035] In order to solve the above problems, the present invention first proposes a virtual magnetic core constructed using the vector magnetic circuit principle, such as Figure 1 and Figure 2 As shown in the figure, it is a virtual magnetic circuit constructed by multiple vector magnetic circuit elements, which can partially or completely replace the traditional magnetic core or air core to form a closed magnetic circuit, and its magnetic conductivity is similar to or even better than that of the real magnetic core, forming a virtual magnetic core. By reasonably configuring each vector magnetic circuit element and the circuit elements connected to it, the magnetic circuit parameters of the virtual magnetic core can be adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit can be controlled, the excitation current (magnetomotive force) of the magnetic circuit can be adjusted, and the active power and reactive power of the magnetic circuit can be affected.

[0036] Furthermore, the vector magnetic circuit element constituting the virtual magnetic core is formed by connecting a capacitor element to the magnetic induction closed coil to form a vector magnetic circuit element with a negative magnetic resistance value and a positive magnetic induction value, such as Figure 3 According to the vector magnetic circuit theory, the expression of the equivalent magnetic circuit impedance under sinusoidal excitation is: . Where Z is the equivalent magnetic impedance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force,C is the capacitance value of the capacitor element, R is the resistance value of the magnetic induction closed coil. Its magnetic impedance includes a negative magnetic resistance term and a positive magnetic reactance term, in which the negative magnetic resistance term can partially or completely offset the magnetic resistance of the target magnetic circuit.

[0037] Furthermore, the vector magnetic circuit element constituting the virtual magnetic core is an active circuit element with negative resistance connected to the magnetic induction closed coil, such as Figure 4 As shown, its magnetic circuit characteristics show negative magnetic induction, and the equivalent magnetic reactance value is: Where X is the equivalent magnetic reactance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, - R It is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element. Its magnetic impedance is a negative magnetic impedance term, which can partially or completely offset the aforementioned positive magnetic impedance, so that the magnetic impedance of the entire magnetic circuit is approximately equal to or less than the magnetic impedance of the real magnetic core.

[0038] Furthermore, the vector magnetic circuit elements in the virtual magnetic core can be arranged in a variety of ways along the magnetic flux direction, including series, parallel, cascade, and even in a nested structure in space. Vector magnetic circuit elements with different arrangements correspond to different magnetic circuit parameters, and through their unique configuration, they have different effects on various variables in the magnetic circuit.

[0039] Furthermore, the vector magnetic circuit elements in the virtual magnetic core can adopt different winding forms and turns configurations according to design requirements, such as rectangular, circular, polygonal and concentric structures, etc. Figure 5 Vector magnetic circuit elements with different geometric topologies and winding methods give the magnetic circuit different equivalent magnetic circuit parameters, and have different effects on various variables in the magnetic circuit through their unique topological structures and layout methods.

[0040] Furthermore, the geometry, size, type and quantity of the virtual magnetic core, and the required vector magnetic circuit elements are determined by the actual application requirements, such as Figure 2 shown.

[0041] In addition, in order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention designs an application method of a virtual magnetic core, such as Figure 6 As shown, virtual magnetic cores and conductor coils can be used to construct various electromagnetic devices such as reactors, transformers, and motors that use alternating magnetic fields as media.

[0042] Further, according to the application method of the virtual magnetic core, for the target magnetic circuit, the following steps are taken to achieve the target magnetic circuit under the preset target magnetic flux condition, to minimize the magnetic impedance of the magnetic circuit and reduce the magnetic circuit excitation current (magnetomotive force), as shown in the schematic diagram. Figure 7 As shown, the details are as follows: S1. Calculate the magnetic circuit parameters before adding the virtual magnetic core according to the physical structure of the target magnetic circuit and the actual working conditions (such as frequency, temperature, etc.), including the magnetic flux, magnetic resistance and magnetic reactance of the magnetic circuit; S2. Determine the specific application form of the virtual magnetic core (such as partial replacement or complete replacement), and determine the number and position of the vector magnetic circuit elements in the virtual magnetic core in combination with the calculated magnetic circuit parameters, and calculate the magnetic circuit parameters of these vector magnetic circuit elements; S3, adding the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core; S4. Without affecting the normal operation of the equipment, the negative magnetic circuit parameters (such as negative magnetic resistance and negative magnetic induction) of the vector magnetic circuit elements in the virtual magnetic core are used to gradually weaken the positive magnetic circuit parameters in the magnetic circuit. By continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, the magnetic impedance characteristics of the magnetic circuit are optimized to ensure that the target magnetic circuit minimizes the excitation current (magnetomotive force) of the target magnetic circuit under the preset target magnetic flux conditions, so that the virtual magnetic core reaches or exceeds the real magnetic core in key performance indicators.

[0043] Furthermore, in the application method of the virtual magnetic core proposed in the present invention, in step S1, the method is applicable to any magnetic core that can form a closed magnetic circuit, and does not impose specific restrictions on the physical properties of the target magnetic circuit, such as shape, material or structure.

[0044] Furthermore, in the application method of the virtual magnetic core proposed in the present invention, in step S3, the magnetic circuit parameters of the selected vector magnetic circuit element can be time-invariant magnetic circuit parameters (such as metal conductors) or time-varying magnetic circuit parameters (such as superconducting materials). As long as the application does not affect the normal operation of the target magnetic circuit, the specific form of the magnetic circuit parameters is not limited.

[0045] Furthermore, the application method of the virtual magnetic core proposed in the present invention is applicable to any electromagnetic device including a magnetic circuit structure, including but not limited to reactors, transformers and motors. In addition, there is no specific restriction on the specific form of the target magnetic circuit, such as physical properties such as shape, material and structure.

[0046] The virtual magnetic core constructed by the vector magnetic circuit principle proposed in the present invention and its application method are verified below. The above design scheme is applied in practice, and the feasibility of the present invention is verified by the experimental device constructed. The verification device consists of a signal generator, a power amplifier, a target magnetic circuit, a power analyzer, a recorder, an LCR tester, a voltage differential probe and a high-frequency current probe. In the experiment, the signal generator and the power amplifier drive the excitation windings of the virtual magnetic core and the traditional magnetic core to form a closed magnetic circuit and generate an alternating magnetic flux. The LCR tester is used to measure the circuit parameters of the vector magnetic circuit elements in the virtual magnetic core, and the voltage differential probe and the high-frequency current probe capture the primary voltage, excitation current and secondary voltage. The experimental data are recorded and analyzed by the power analyzer and the recorder. Finally, the magnetic circuit parameters of the target magnetic circuit are calculated based on the collected experimental data, so as to verify the effectiveness and feasibility of the design and application method of the virtual magnetic core.

[0047] The experimental goal is to replace the air core in the transformer with the virtual magnetic core constructed using the vector magnetic circuit principle by applying the virtual magnetic core constructed using the vector magnetic circuit principle and the application method thereof as described in the present invention, thereby weakening the magnetic impedance of the target magnetic circuit, reducing the excitation current, improving the coupling ability of the target magnetic circuit, and minimizing the excitation current (magnetomotive force) of the target magnetic circuit, so that the virtual magnetic core transformer is close to or better than the traditional magnetic core transformer in key performance indicators, so as to verify the feasibility and engineering application value of this patent in electromagnetic devices.

[0048] In the experiment, the target magnetic circuit is realized by an air-core transformer. The primary and secondary windings are made of 0.1mm×100 Litz wire and are wound in parallel on a magnetic core frame of EC90 specification. The number of winding turns is 23. Under no-load conditions, the primary voltage of the air-core transformer is measured. u 1 , Secondary voltage u 2 and the excitation current i 1 ,like Figure 8 As shown, the magnetomotive force and magnetic flux of the air-core transformer can be calculated. Based on Kirchhoff's magnetomotive force law in vector magnetic circuit theory, the magnetic circuit is analyzed using the above measurement data, and it is calculated that the magnetic resistance parameter of the magnetic circuit is 7.85×10 8 H -1 .

[0049] Since the transformer composed of air core only has magnetic resistance parameters, in order to weaken the positive magnetic resistance parameters in the magnetic circuit, a vector magnetic circuit element with negative magnetic resistance is added to the target magnetic circuit to form a virtual magnetic core, such as Figure 7 The magnetic circuit element is wound with 0.1mm×400 Litz wire, with 43 turns, and connected to a capacitor.C =0.47μF. At the operating frequency of 41.2 kHz, the transformer's magnetomotive force reaches its minimum. At this time, the primary voltage u 1 , Secondary voltage u 2 and the excitation current i 1 In phase, such as Fig. 9 When the secondary voltage u 2 When the primary voltage is 45.14V, u 1 is 45.54 V, the excitation current i 1 is 0.334 A, the voltage of the magnetic circuit components u c is 113.1V, current i c The current is 14.25A, and the coupling coefficient of the transformer is increased to 0.990. Under this condition, the power factor of the transformer reaches 0.999, indicating that its magnetic resistance parameter has been effectively weakened to zero. However, the introduced magnetic circuit element also produces a magnetic reactance parameter, whose value is 1.00×10 7 H -1 , verified Figure 7 correctness.

[0050] Since there are still positive magnetic resistivity parameters in the target magnetic circuit at this stage, in order to further optimize the magnetic circuit performance, magnetic circuit elements with negative magnetic induction parameters are added to the constructed virtual magnetic core, such as Figure 7 Specifically, two magnetic circuit elements with negative magnetic induction parameters, each with 2 turns and wound by DuPont wire, are introduced into the virtual magnetic core, and their equivalent negative resistance value is -5.8Ω. After adding these magnetic circuit elements, as shown in Fig.10 As shown, while maintaining the same secondary voltage u 2 Under the condition, the excitation current i 1 When the current drops to 20 mA, the magnetic impedance of the magnetic circuit drops to 6.07×10 4 H -1 , achieving the minimization of the excitation current (magnetomotive force), verifying the effectiveness and feasibility of the virtual magnetic core constructed using the vector magnetic circuit principle and its application method proposed in the present invention.

[0051] To further verify the effectiveness of the virtual core, the magnetic circuit performance of the transformer using the traditional core and the virtual core was compared. The traditional core is composed of a pair of EC90 PC40 ferrite cores with a mass of 660g; while the transformer composed of the virtual core has a mass of 270g, of which the mass of the primary and secondary windings and the winding skeleton is 52g, and the mass of the additional vector magnetic circuit components is 218g. Compared with the traditional core, the mass of the virtual core transformer is reduced by 59.1%, realizing the lightweight design of the transformer.

[0052] Fig.11 and Fig.12 The primary voltage of the transformer under the traditional magnetic core and virtual magnetic core is shown respectively u 1 , Excitation current i 1 , Secondary voltage u 2 and load current i 2 The results show that the virtual core can not only achieve magnetic circuit performance similar to that of the traditional core, but also significantly reduce the weight and volume of the electromagnetic device, further verifying the effectiveness and feasibility of the virtual core constructed based on the vector magnetic circuit principle and its application method.

[0053] In summary, the present invention proposes a virtual magnetic core constructed using the vector magnetic circuit principle and its application method. The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. The target magnetic circuit is not limited to the transformer. Any electromagnetic equipment that can include a closed magnetic circuit and equivalent modifications or changes made by ordinary technicians in this field based on the content disclosed by the present invention should be included in the protection scope recorded in the claims.

[0054] The above descriptions are only some embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A virtual magnetic core constructed using the vector magnetic circuit principle, characterized in that: A plurality of vector magnetic circuit elements, a plurality of circuit elements, and a plurality of excitation windings are coupled to the magnetic flux loop of the virtual magnetic core to construct a virtual magnetic circuit and form a virtual magnetic core, and the virtual magnetic core is used to replace a part of the traditional magnetic core or completely replace the traditional magnetic core; by configuring each vector magnetic circuit element and the circuit elements connected thereto, the magnetic circuit parameters of the virtual magnetic core are adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit are controlled, the excitation current of the magnetic circuit is adjusted, and the active power and reactive power of the magnetic circuit are affected.

2. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1, characterized in that: The vector magnetic circuit element forming the virtual magnetic core is formed by connecting a capacitor element in the magnetic induction closed coil to form a vector magnetic circuit element with negative magnetic resistance and positive magnetic induction value; the expression of the equivalent magnetic circuit impedance under sinusoidal excitation is: ; Where Z is the equivalent magnetic impedance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force, C is the capacitance value of the capacitor element, R is the resistance value of the magnetic induction closed coil; its magnetic impedance includes a negative magnetic resistance term and a positive magnetic reactance term, wherein the negative magnetic resistance term can partially or completely offset the air magnetic resistance of the target magnetic circuit.

3. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1, characterized in that: The vector magnetic circuit element that forms the virtual magnetic core is an active circuit element with negative resistance connected to the magnetic induction closed coil. Its magnetic circuit characteristic presents negative magnetic induction, and the equivalent magnetic reactance value is: ; Where X is the equivalent magnetic reactance of the vector magnetic circuit element, N Indicates the number of turns of the magnetic induction closed coil, - R It is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element; its magnetic impedance is the negative magnetic reactance term.

4. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1, characterized in that: The vector magnetic circuit elements in the virtual core are arranged along the magnetic flux direction in a variety of ways, including series, parallel, cascade, or forming a nested structure in space.

5. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1, characterized in that: The vector magnetic circuit elements in the virtual magnetic core adopt rectangular, circular, polygonal and concentric structures as well as different winding forms and turns configurations according to design requirements. Vector magnetic circuit elements with different geometric topologies and winding methods give the magnetic circuit different equivalent magnetic circuit parameters.

6. An application method of a virtual magnetic core constructed using the vector magnetic circuit principle as claimed in any one of claims 1 to 5, characterized in that: Virtual magnetic cores and conductor coils are used to form various electromagnetic devices using alternating magnetic fields as media, including reactors, transformers, and motors.

7. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 6 is characterized in that: For the target magnetic circuit, in order to achieve the target magnetic circuit under the preset target magnetic flux condition, reduce the magnetic impedance of the magnetic circuit and reduce the magnetic circuit excitation current, as follows: S1. Calculate the magnetic circuit parameters before adding the virtual magnetic core, including the magnetic flux, magnetic resistance and magnetic reactance of the magnetic circuit, according to the physical structure of the target magnetic circuit and the actual working conditions including frequency and temperature; S2. Determine the specific application form of the virtual magnetic core, including partial replacement or complete replacement, and determine the number and position of the vector magnetic circuit elements in the virtual magnetic core in combination with the calculated magnetic circuit parameters, and calculate the magnetic circuit parameters of these vector magnetic circuit elements; S3, adding the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core; S4. Under the premise of not affecting the normal operation of the equipment, the negative magnetic circuit parameters of the vector magnetic circuit elements in the virtual magnetic core, including negative magnetic resistance and negative magnetic induction, are used to weaken the positive magnetic circuit parameters in the magnetic circuit; by continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, the magnetic impedance characteristics of the magnetic circuit are optimized to minimize the excitation current of the target magnetic circuit.

8. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 7 is characterized in that: The method is applicable to any magnetic core that can form a closed magnetic circuit, and does not impose specific restrictions on the shape, material, spatial layout or physical properties of the structure of the target magnetic circuit.

9. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 7, characterized in that: The magnetic circuit parameters of the selected vector magnetic circuit elements are time-invariant magnetic circuit parameters or time-varying magnetic circuit parameters.

Images